Giant Malignant Nerve Sheath Tumor of Lumbosacral Plexus with Intraspinal Extension in a Child with Neurofibromatosis Type 1

Malignant peripheral nerve sheath tumors (MPNSTs) are the leading cause of death in young adults and are one of the most frequent non-rhabdomyosarcomatous soft tissue tumors in pediatric age. These tumors usually occur in young adults from a previously recognized neurofibroma, neurofibromatosis type 1 (NF1), with a noted change in size and pain. This child reached the age of 10 without the presence of the more commonly seen manifestations of NF1. Pseudoarthrosis in children has a high rate of association with NF1, and in this case diagnosis of NF1 was supported by development of MPNST in a pre-existing plexiform neurofibroma.